Search of the person - business always difficult even if his name and a surname are known. Even if at you is on hands of its coordinate, it does not mean yet that it will appear in this place at this particular time. What already to tell about the Internet where the person can disappear under any nickname, to write anything and anywhere to be registered.
1. It is much more difficult to look for the person in blogs, than, for example, on social networks of other format - on such websites as VKontakte or "my World" as in blogs the real name and a surname of the person are less often entered. Often the blog is created for advance of some product or service or for maintaining the anonymous diary. However social networks can help you with this hard business. Often people post data on the blog in the section "Personal Website" (it can be called differently). Of course, often it is necessary to be in friends at the person to look at such information, but in some cases such opportunity after all is. Do not neglect social networks if they can help you.
2. Other path - search by interests. At first just try to enter keywords which on subject can be connected with the blog in the searcher. The list of the websites where these words meet will be provided to you. It is possible to use both standard search engine, and search on the separate websites (for example, in "LiveJournal") intended for creation of online diaries. Look for not only records by the set keywords, but also comments. Do not neglect communities. However, to find the person in blogs thus, it is necessary well his nobility. Interests, stylistics inherent in its written language, a circle of subjects - all this that information which should you be known already in advance. Try search by more standard parameters: to the city where the person lives, date of birth and so on. Keep in mind as well the IP address: in some blogs there is a function of saving the IP address of users who leave comments on records.
3. Make the list of diaries which presumably belong to the required person. Do not stop on the analysis of diaries, walk according to the list of friends: it is quite possible that nicknames in itself will tell you about much. Somewhere you will notice the evidence of interests and hobbies (a name in a foreign language) or catch the word known only to this person. Though, maybe, you also should not carry out such laborious work which will probably not bring success. Perhaps, the blog by the person here, on a surface, and to you is worth clicking a mouse to read it.