Saying goodbye to 2009 won't, alas, let us say goodbye to many of the year's top threats, which promise to linger and persist into 2010, even as the New Year brings new threats, as well as new versions and varieties of the old ones.By now we're accustomed -- or should be -- to each year's threat environment being a little (and some years a lot) worse than the year previous. The threats our systems face evolve along with the evolution of those systems -- and sometimes evolve at a faster pace than protective measures.

The targets for those threats evolve, too, with 2009 seeing small and midsized businesses increasingly identified as prime cybercrook targets, a trend that's unlikely to diminish in 2010.

Tough economic times contributed to SMB vulnerability: security is essential to doing business, but all too easily perceived as less than essential to an already constricted bottom-line.

Some of the vulnerabilities that persisted through 2009 and are likely to linger into 2010 -- and probably 3010 for that matter -- are among the most easily and economically avoidable. Unpatched security holes tops the list here, precisely the sort of negligence that Conficker and other attacks take ongoing advantage of.

New uses bring new abuses. The explosive rise of social networks led to an explosive rise in the exploitation of social nets and their users. Look for this one to continue to grow next year.

Even without the season's deluge of holiday-themed spam and spam scams, it's now news that spam remains a queue-clogging problem, and one that is showing no signs of slowing.

And next year, as this year, and any other year you care to name, human errors, as well as security sloppiness and laxity, will continue to dog small and midsized businesses.

The more things change, the more some things, including security threats, remain the same.