EXIF (Exchangeable Image File) Data is something not alot of people know about but should. This form of data is embedded in pictures and in some cases other files. This has in previous cases have revealed identities of people who did not want their identities revealed. If you are taking pictures with your mobile phones and uploading them to social sites, then there is a chance you are releasing your location and computer information along with that particular picture.
Here are some links and Apps that can help you combat this:
Online EXIF Data Strip - Upload an image file and the sites strips the data for you.
Geosetter - a freeware tool for Windows (XP or higher) for showing and changing geo data and other metadata (IPTC/XMP/Exif) of image files (e.g. images taken by digital cameras).
Always be safe and check the images you plan on putting online before actually putting them up. Simple mistakes like this can be very damaging to your Anonymity.