Is it worth advertise on sites that have not given you 1 lead?

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ok let me explain this a little better otherwise it would be an obvious "NO" answer based upon the subject line.. i have a site i sell on that is like ebay but doesnt get the traffic like ebay.. there fore obviously i need to do some advertising so i made an livejournal, myspace, twitter and facebook page for it. the problem is as far as i can tell i havent gotten 1 buyer from any of them! another concern i have is the fact that my fb page is attached to my profile which means locals can see a picture of me which for safety reasons im not too fond of.. the time it takes to do the html, upload pics, get links etc for over 70 items just to post it on sites that dont seem to be working seems insane.. i feel that i could take that time to add items or be able to work on other hobbies i have neglected so i wont lose my mind lol.. now i know a lot of people have had good luck with sites but myspace seems to be going under and livejournal isnt that popular anymore so i was thinking about axing at least the myspace and then facebook for safety reasons.. am i stupid in giving up on these sites? i never get around to updating them due to the time it takes so part of it is my fault on why they have failed but even when i did it all the time i got NOTHING! i feel that my time is better used elsewhere like double listing in craigslist etc.. or should i just bite the bullet and work on the sites even though it takes a lot of time and keep being disappointed by them?