[TheLastSuperman]

^ Yes as its your database respectively. As Dave mentioned though in some countries there are rules or regulations rather that must be followed such as if a person asks for their account to be deleted you should comply OR rename and obfuscate all posts by the user so no one could identify that renamed account as the old one in any fashion - that will also suffice from past experience. It differs per country and state and also when dealing with user data despite you owning the database, everyone still has rights including invasion of privacy so make sure your Terms of Service/Condition state that you explicitly own the data they submit whether public or personal and you can and will use it in any fashion to help promote the site etc or similar and you should be fine however I'm not a lawyer so head my words with caution and do research to ensure its done correctly. * The reason this needs to be in TOS/TOC is the fact when users register on the forum, they must click the checkbox that they agree to said terms and conditions, they just agreed that what you stated in your TOS was acceptable and if they didn't read well, they will when an issue arises and they confront you regarding it, then you show and remind them that they themselves agreed to the TOS in order to use and participate on the site.

Since you're specifically asking this I'm pretty sure it's for a good reason so with that being said I would consult a local attorney to ensure you're going about this the correct way IF its that important to you respectively.