usually when im testing and using new online services, i give them about a month, see if i actually need them in the first place, see how i interact with them and the like. its been well overdue me summing up what i think about some of them. here they are in point form:

flock - good in idea and premise, not the best in implementation

flickr - excellent. i couldnt be happier with flickr, not that i take many photos myself, but i just enjoy the freedom of going online and being able to find photos, using an intelligent tagging system. you can tell a good service when it is adopted by a lot of people, and people's own mini flickr feeds directly on their sites and blogs is a good indication at the easiness and depth to the flickr service. i am more than happy with it :)

gmail - everyone needs email, i choose a web based one so i may check it at uni and at any where else i may be. great storage capacity and good archiving and searching features. very good.

tada list - tada lists are great. easy lists for anything anytime. i currently only have 4 lists, but they are for what i need. such as what to download, what i need to buy (in terms of gifts, clothing, etc), a simple todo list and uni assessments i need to complete. this service is simple and clear in implementation and great if you need a bit of flexibility in the lists you keep, such as accessibility anywhere with net access, a nice interface etc.

google reader - not the best service...very slow and to tell the truth, the interface is a bit shitty and stymied (cos everything is a bit too large and screen crowding). i am not going to use this service anymore till it speeds up considerably and has a bit more of a google interface than one that looks half baked

these are the main services i have been using and anything i havent mentioned probably doesnt appeal that much to me. of course, if you have any good services you use that i probably havent thought of (i dont think that much :P) then pls comment and let me know, cos im really wanting to try out some new ones soon :)