It looks like MacHeist is giving away a free copy of DEVONthink, an information manager.
It is the Personal version of DEVONthink, not DEVONthink Pro Office. Here is more information from their site:
This is a full license for DEVONthink Personal version 1.9.16 and can be upgraded to the upcoming version 2.0 for $20. Please be sure to register before you do so, as DEVONtechnologies needs to have you included in their database before doing so. And if you need even more power, you’re able to cross-grade to their Pro or Pro Office versions.
If all you need is the Personal version, you can’t beat free.
MacHeist is doing it via a “Tweetblast”, which means they want you to claim the free software via Twitter. Here’s the website with instructions.
Enjoy!