ThePort, a startup which helps media companies and non-profits add social networking features to their sites, has raised an additional $500,000 in funding. CEO Bob Cramer tells us that the cash, which comes from existing investors, is an add-on to the $4.1 million that the company raised in a second round led by American City Business Journals a year ago. He says that the company, which is not yet profitable, will bring in about $2 million in revenue this year and expects revenue to reach $5 million next year.