You’re careful about what you post online. You know Facebook and Twitter posts can harm your dating and job prospects. And thieves can use the sites to target you.

But there’s much more to maintaining your security and privacy. Criminals and marketers have found new ways to use Twitter and Facebook. If you’re not paying attention, it’s easy to get taken.

Don’t be fooled by shortened URLs

Twitter limits posts to 140 characters. So, shortened URLs (Web addresses) are common. You’ll also see them on other sites. URL services create the shorter addresses.

Unfortunately, unless you take extra steps, you don’t know where the link leads without clicking it. You could be sent to a porn site or worse—an attack site.

TweetDeck, a desktop program, will protect you. Or use the Long URL Please add-on for Firefox. Both reveal full URLs. Sites Untiny and PrevURL show full URLs in any browser.

Beware “friends” in need

Unsurprisingly, criminals are stealing Facebook log-in credentials. Accounts contain sensitive information, but there’s an easier way to profit.