Allot of traffic on internet dating sites happens on the weekend.  This is due mainly because the majority of us who don't have a date are looking for one and devote our free time (ie the weekend) to it.  The week tends to be hectic with work and life in general, so most of us are able to devote more time to online dating on the weekends.  It's a great time to read through all the profiles and decide which ones you would like to make contact with or engage in conversations.  Free online dating services have the added bonus of not charging you a fee for communicating with one another.