Brian, follow the link to learn about elgg_get_entities. That is how you are going to query the database to find blogs. It supports all kinds of parameters for which entities you want.

ok ill try thanks

A possible way to implement this would be to use the Expirationdate plugin as a basis. This plugin already implements a cronjob that expires / deletes entitities after their valid time has expired. There are functions included (to be useable by other plugins) to set/unset the valid time.

What you would need to do is to define the valid time (for example 60 days) of a blog entry when it is created. This should be possible by using an Elgg event handler.

Put CSS in your site plugin to postition them as needed.

I have a CSS snippet that styles system messages like Twitter Bootstrap, and the first block sets the position. 

Thanks

I will try that