When you release a Windows Phone app you get one passive marketing channel for free – the new apps list. Fortunately for Microsoft and end-users, but unfortunately for you, more than 100 new apps are released each day. So this free theoretical exposure boost dries up pretty quickly.

If you have an advertising budget you can spread the word by pouring money into marketing. But most of the indie developers have no (or very small) advertising budgets and even when you have some money, there are plenty of ways to get some exposure for free.

Here’s a list of 25 techniques I was able to think of (or notice others use) to promote WP7 apps:

0. Make a great app that solves a real problem or brings user experience to a new level for a problem that has been solved before. Or just make a great and addictive game.
   Obviously the better and more unique your app is, the easier is to spread the word about it. And if your app is just a lousy exercise with no particular use or fun factor, there’s hardly a technique to get it anywhere. So obviously it all starts with making an app you believe in.
1. Ask developers (and soon average users) to beta-test your app.
   Not only this will help polish and refine your app, but you are recruiting first members of your “street team” this way. You can find people willing to help you on Twitter or App Hub forums and probably some other places. If beta-testers like your app, they are quite likely to help you spread the word around once your app is released. For now you can ask developers with unlocked phones to sideload your app. But when Mango hits the streets you will be able to publish your beta through the official channels.
2. Make an attractive Tile.
   We have already established that you have a good app. So this statement doesn’t apply to you. However your Tile is the first thing people see when they browse or search the marketplace. Especially when yours isn’t the only app addressing the same problem a good or bad Tile could make a huge difference. So make yours stand out. And not in a bad way.
3. Start with a free app
   Your app could be your best marketing tool. It’s no secret that way more people download free apps than paid apps. Even with free and fully functional trial you are looking at a fraction of downloads you can get with an absolutely free app. You can make a premium version later and charge for it, or you can monetize your app with advertising. And hopefully in-app purchases will come soon enough. You can even go from free to paid with the same app later, like Chicks’n’Vixens did. And it was the #1 paid app for a couple of weeks because of this trick. This technique might be slightly over you “gray area” line, so it’s up to you to decide. But I would argue it isn’t wise to limit your reach by charging 99 cents at this stage. (unless your app has an expiration date)
4. Make a video demo of your app
   It’s not the first thing you think about, but it’s way easier for people to watch a YouTube demo of your app than to download and try it. So, many will watch your video even if they wouldn’t download and install it based on your (or someone else’s) description. And you get an extra chance to capture their attention in the video.
5. Join AdDuplex
   I’ve created AdDuplex after witnessing numerous developer frustrations with low-to-no visibility they were getting for their apps. AdDuplex helps developers promote each other’s apps for free. There’s a catch that you have to have some visibility to exchange for extra visibility, but hopefully this list gives you some ideas and results.
6. Tweet about your app
   Tweet about the initial release of your app. Tweet about every update. Tweet about it in-between updates. Decorate your tweets with #wp7 hashtag. Even if you don’t have a lot of followers there are lots of people (and some important and influential people) monitoring the #wp7 tag. Manage to get attention of some of them and it can go a long way from there.
7. Notify your friends about your app
   Let your Facebook friends, tweeps, real-life friends and family know about your app. Even if they don’t own a Windows Phone or have nothing to do with technology. You never know who they’ll be talking to tomorrow or a month from now. And there’s a really good chance they’ll mention your app when appropriate. They are your real friends and family after all and they love you, right?
8. Make a Facebook page for your app
   Making a Facebook page is an easy way to get free promotion from your Facebook friends and get onto feeds of other Facebook users.
9. Create a dedicated Twitter account for your app
   Same as with Facebook but for the twitterverse.
10. Join AdDuplex
    Did you know that if you join AdDuplex by October 1, 2011 you have a really good chance to win a brand new next generation Windows Phone running Mango. Could that be a Nokia Windows Phone? Quite possibly. And this is in addition to free promotion you are going to get through AdDuplex.
11. Make a website for your app
    Or a dedicated section on your website. This would be a place you can direct people to. Showcase the cool features and experiences your app provides. Link or embed all the related activities (Twitter, Facebook, YouTube, etc.)
12. Facilitate the feedback loop
    The more positive ratings your app has in the Marketplace the more likely users will choose it over competition. So, encourage users of your app to rate it. That said, if users don’t like something about your app make sure it’s easier for them to provide you direct feedback than rate it poorly.
13. Tip Windows Phone blogs
    Tip the major (and smaller) Windows Phone blogs about your app. WPCentral, WMPowerUser, 1800PocketPC are just a few of the better known blogs and there are a lot more. Make sure you include a link to your video demo (you made it, right?) and a concise but well written description of your app. Some of the blogs may even post your tip as is (or with only some minor modifications), so pay attention to this step. It’s one of the best ways to boost your exposure.
14. Ask your tweeps to tweet (or retweet) about your app
    I’ve been approached multiple times by my Twitter friends to help spread the word about their apps. Luckily I have very good and smart tweeps, so I never had to tweet about apps I don’t actually like. So I guess it would be awkward if someone asked me to promote an app that I think sucks, but I didn’t want to offend my friend. But since we’ve established that you made a great app in step 0, there’s nothing to be afraid off.
15. Try to get on podcasts
    Windows Phone Dev Podcast has a form you can fill if you want to be on the show. They’ve gotten a lot more popular since their launch (and for a good reason) so I assume it’s harder to get on the show, than it was when they’ve just started, but it’s still doable (at least the form is still there). Other podcasts don’t have a form like that, but I bet you can get on some of them if you have something to say and try hard enough (don’t try too hard though). Here are a few podcasts that are Windows Phone related (or at least had some WP7 related episodes) – Windows Phone Radio, Jesse Liberty’s Yet Another Podcast, DotNetRocks, Hanselminutes, Herding Code.
16. Add social network integration to your app
    Let users of your app tweet, post to Facebook, etc. directly from the app. Add your @yourAppsTwitterAccount to the tweets. Pictures Lab does it, SurfCube does it and lots of games do it. People want to brag about their achievements on Twitter or Facebook. Help them and help yourself.
17. Try to get featured in the Marketplace
    All it takes is making a really great app and getting noticed by the team. Easy, right? Seriously though, make sure your deliverables (description, screenshots, tile and background image) are top notch and if you take steps in this list seriously there’s a good chance they’ll notice. Plus keep an eye on special opportunities like “Spring Cleaning”. The effect of being featured is quite substantial.
18. Mention your app in your social media (and other) profiles
    Mention and link to your app from your profiles on social networks and other communities you participate in. People often check profiles of the people they are communicating with and there’s a chance to grab their attention.
19. Participate in relevant communities
    I guess this goes without saying. Most likely you are already participating in some community related to the problem your app solves. But don’t forget to mention your app where it’s relevant. A word spreads fast in targeted communities. And don’t forget Windows Phone targeted communities like App Hub forums, XDA developers and everythingwm to name a few.
20. Join AdDuplex
    In case you’ve published your app through Yalla Apps you are entitled to 20,000 free ad impressions campaign on AdDuplex network. How’s this for a free promo?
21. Temporarily change your avatar on social networks to your app’s Tile
    Your friends and followers will notice and be interested to learn what’s that about.
22. Help other developers promote their apps via social media.
    Tweet, retweet and otherwise help fellow developers promote their apps. They will be more than happy to return the favor.
23. Bring your app to the attention of key people at Microsoft and/or WP7 community.
    Wordament is a great game. That said I first heard about it from Brandon Watson on Windows Phone Radio (if I’m not mistaken). Recently Joe Belfiore has tweeted about it. That’s one of the nicest free promotions you can get. But you have to make an effort to bring your app to their attention. Do not spam these nice people, but it’s pretty reasonable to mention your app to them when it’s relevant. If you go to some bigger WP7 related event be prepared and don’t be shy to approach community leaders and demo your app to them. They won’t bite… I guess.
24. Add “Easter eggs” to your app
    Add some nice undocumented features or other delighters to your app. People are prone to wanting to share their discoveries with their friends and word of mouth is the best marketing vehicle.
25. Join AdDuplex
    Did I mention you should join AdDuplex?

This is only a short list of options I’ve written down while exercising my “idea muscle”. Feel free to amend it in the comments below.