(
First, let me declare my bias as I am professionally involved with this topic so take what I am saying here with the proverbial grain of salt.)
A blog is one of the best things you can have to promote your sales whether your listings are here on eBay or any other selling venue.
Every person attempting to build a successful business should have their own domain name and website. Having a blog integrated with that website is a very good thing.
Since eBay is closing down blogs, and if you have been writing one, you really should consider making the step to your own website with blog. This kind of site is easy to maintain and provides a great base from which to build your business and project your online identity.
There are a lot of good sources for this kind of website so shop around. Be sure you understand what features a site offers and what those features mean in the process of promoting your business.