1. A computer-implemented method for managing online user profiles, the method comprising: generating, by at least one processor, a prioritization table based on impression counts associated with a plurality of URLs; retrieving, over an electronic network, textual data associated with the plurality of URLs, the retrieving being performed based on the prioritization table, such that URLs with higher impression counts have their textual content retrieved before URLs with lower impression counts; generating, and storing in a database, one or more keywords in relation to each of the URLs, based on respective textual content retrieved for each of the URLs; receiving information about online activity of a user, the information including at least a unique user ID and a URL requested by the user; searching the database for one or more keywords stored in relation to the requested URL; and generating or updating, by the at least one processor, a user profile of the user to include the one or more keywords stored in relation to the requested URL.