Firstly, there are plenty of discussions on whether the sandbox exists or not - let's not make this one of them ;)
For those who consider their site to be sandboxed what limitations (other than ranking) do you consider have been placed on your site?
e.g. 1. Outbound links from a sandboxed site do not increase the value of the site linked to.
2. Inbound links from other sites are ignored until you are released from the sandbox.
3. If you have purchased an expired domain in the hope of bypassing the sandbox does this only work if there are old links pointing to your site or does the single fact the domain itself is old cause you to rank.
4. When one of your sites is "released" do the other sites get released quicker (i.e. other sites with Whois info the same).
5. Do links from other sandboxed sites (as opposed to older sites) increase your sandboxed ranking (e.g. position 350 to position 250).
I look forward to hearing any theories or research you may have in this area. Yes, I am an avid "nay-sayer" to the whole sandbox thing but that is neither here nor there for this particular discussion.