Probably more for Sam than anyone else.

Be careful, if you post an apk of your free app here, somebody will try to take the apk, remove the signature, and upload it as a paid version on the market!

QuoteHow is it possible ?
Google does not check your apk signature when you upload a software.
Even if you signed yous apk with you key, somebody else can put this on his google account.
The signature can be deleted easily if needed.
He can change the title of your app, so nobody see it, but he cant change the apk name nor the icon.

Why do we post our apk here ?
To have testers, to correct bugs, to have a perfect look and feel before put it on the market.
Because on the market people are rude, we have only one chance, so we need to avoid bugs.
And when we put our app online, we want to choose if its paid or free (with ads or not).

What is the problem ?
If DavinciDevelopers steal and upload your app, he will lock your pak name.
2 apps cant have the same name on the market.

You may have a name like com.myname.myapp.apk
Where "myname" is the same in every app you do.
If he take that, this is a major issue for you because you will be associated to him on every search (google.com, market...).

So, you will have to change your app name and maybe your company name....

Within 1 or 2 days, the market is parsed from androlib, androidzoom, appbrain... and its done. Google.com will see those websites, and you are trapped.

You will have your buggy app on the market, some people will pay for that, the thief will have some money, and every users will have a bad opinion of your app.

http://forum.xda-developers.com/showthread.php?t=900907
http://www.villainrom.co.uk/forum/content.php?244-WARNING-Attention-App-Developers&s=f5b23051aedb74a489ebfda9e084042b