Users in MySQL? Was I hacked? Is it a plugin?

Hi,

I was in the process of moving my site from one host to another, when I discovered in my MySQL database for wp_xbvu9w_users that there were three users that I never heard of. I deleted them in my new install on my new host, and the new host seems ready for me to switch it over.

But I’m not sure if these users are connected to some plugin that I use? Would subscribers to posts/pages I have on my site show up here in this database (and thus maybe I should add them back in)?

Thanks for any comments!

Michael