Virtually all the information you could ever want is online today, available right at your fingertips. This is especially true for family history and genealogy. You can view your family tree, search surname lists, or post queries for distant relatives online.
Spelling Variation
Tracing your surname and your family lines can be difficult, in part because of the transient nature of surnames in times past. In the nineteenth century and before, there was no such thing as standardized spelling; names were spelled the way they sounded to the person writing them down. This accounts for much of the variation in surnames today. Take a simple surname like McIntyre, for instance, and search for it in surname lists. You'll find variations MacIntyre, McEntyre, and MacEntyre.
Transient Surnames
Aside from the spelling variations you'll find in surnames lists, genealogy and surname history can be tricky because some ancestors may have actually changed their surnames. Contrary to popular belief, surnames were not commonly changed at Ellis Island, but many Jewish, German, and Eastern European immigrants changed their surnames to "Americanize" them as they settled in and became naturalized as U.S. citizens. In some common Anglicizations of surnames, Schwartz became Black, Bach became Beck, and Woulfe became Wolf.
Ancestors may have also changed their surnames to avoid a social stigma or to disassociate themselves with their families. In still other cases, people were essentially forced to change their surnames. During the British oppression of the Irish, for instance, when people identified as Irish or having Irish surnames could not vote or own property, many Irish families dropped the traditional Irish "O" prefix to their surnames. Thus O' Connor became Connor, and O' Kennedy became Kennedy.
Searching Surname Lists
Whatever surname you're searching for, and whatever difficulties you face in tracing your family lines, the internet is a prime resource. The message boards, family trees, and surnames lists available online are invaluable. You can find these sites using a simple Google search, and then subscribe to the message boards or the RSS feeds of any genealogy blogs you want to follow. Search OneGreatFamily's Surname Lists.