[irabren]

Be careful - I bought a mobi Book but it won't open on the Kindle - (encrypted )
There is a way to do a work around - but it is a lot of trouble ( see post: from Chobitz: "I just converted and sent myself an E-book ) in "tips and Tricks section "..... )
The free books on Mobi - will more likely work on Kindle.

 

[pidgeon92]

Yes, we've had a few threads about Mobi DRMd books that will not open.

 

[MonaSW]

Amazon states in the manual that DRMed Mobipocket books can't be read on the Kindle. So unless you know the Mobipocket book does not have DRM, do not buy it.