Recently many website owners using Joomla 1.5 on a Bluehost hosted site received a confusing and potentially very upsetting email. 

Bluehost is no longer supporting sites using Joomla 1.5.  Such sites will be suspended and migrated via an automated upgrade to Joomla 2.5 by Bluehost. Bluehost is recommending that users migrate ahead of time on their own to avoid any complications.

Complications?

Yes, complications. Unfortunately with a systemized upgrade, there are likely to be a number of complications to individual websites.  These problems might include incorrect migrations, loss of information, sites unavailable for an uncertain time during the migration, loss of custom codes or themes.