There seems to be plenty of websites that offer online conversion to Conservative Judaism. Are these real? Has anyone done this? Is it a scam?
Such a conversion would not be accepted in the Conservative movement. A site offering an online-only Conservative conversion is at best extremely misguided, and possibly a scam.
For starters, Conservative Judaism would not accept a "conversion" that did not include mikvah and (for men) circumcision. This doesn't even come up in the law committee responsa on conversion; it's taken as a given.
Conversion requires individual study with a rabbi. I have heard of people in isolated locations who have no local rabbi doing some of their study remotely (for example via Skype), but I've never heard of one who was able to complete a conversion that way (including the beit din). This is anecdotal evidence only, I know. The Conservative rabbis I know expect a convert to become part of a local Jewish community, which means in person.
Conversion is a major life changing decision that cannot be thrown out like the whims of an online dating account and something like this should be avoided as not being genuine. Any responsible rabbi will require a period of study and a knowledge test before proceeding.
Additionally if someone tells you that you can convert to Judaism and it does not require all of the following 1. acceptance of the entire Torah both in practice and belief. 2. If male either circumcision or hatafas hadam bris. 3. mikvah 4. an understanding that when the beis hamikdash is rebuilt you will have to bring a sacrifice then the conversion being offered is a scam