The issue to be addressed extends far beyond surfjunky.com, E-commerce is a gamble. Because you have no physical contact with a business, and because of the ease with which a business can disappear it is very difficult to protect yourself against fraud. When considering whether or not to use a site such as surfjunky.com you need to evaluate whether or not you can afford to lose out. If there is a financial risk, it may be safer to use a recognised site. On the other hand so long as you have parted with no financial details, in the case of surfjunky it seems the most you would lose is a few hours of your time.
It may annoy you to lose that time, and you will be earning money for someone else, but is it really a scam in the true sense of the word? Probably not, although it would certainly be dis-honest of the site holder.
As well as evaluating the cost to yourself if a site does fail to keep its promises, you should also take steps to ascertain the likelihood that it will happen, consider installing a utility such as WHOIS so that you can access the domain registry records. If it appears that the details provided are phoney, the chances are that the site is a hoax. Whilst false WHOIS details do not provide confidence, they are not necessarily proof of a phoney site. Many people do not register (or indeed update) correct WHOIS details for their domains.
If a site requires financial details upfront, or requests anything that you would not normally provide, think twice about providing them. Most sites will allow you to register and ask for payment details only when a payment is due. It would even be worth creating a Bank Account (with no credit facilities) to provide for payments, this will at least 'ring-fence' your money so that even if a fraud does occur the fraudsters are less likely to gain access to your other finances.
You can also reduce the risks by using a seperate email address for registration, this means that if the scam involves selling email addresses to apammers you don't end up with an ever growing inbox.
As a rule of thumb, if it seems too good to be true, it probably is. But it is down to you as the individual to make a decision on whether is worth the risk.
Although it does seem unlikely that surfjunky.com is genuine, it is quite possible that it is not fraudulent. On first examination there appears to be little risk involved in trying it, but there are often threats that aren't quite so apparent. Applying the rule of thumb, getting paid to browse the internet seems far too good an offer. The likelihood of it being genuine is dramatically reduced when you consider that this is essentially payment for doing nothing.
People tend to associate the Internet with getting rich, but the reality is that it's very difficult to make money on the net these days, you are certainly highly unlikely to get there without a lot of work, even criminals are finding less and less benefit to conducting business over the net. As the risk increase, so does the wariness of users, and unfortunately legitimate businesses often get tarred with the same brush.
In conclusion, conducting any business on the net involves certain risks, and each individual must asses whether they are worthwhile. many sites may appear to be scams, but if it does not entail too large a risk on your part then it may be worth trying. Helium.com could easily have turned out ot be a scam, but they asked for no financial details upfront and I enjoy writing, so I took a calculated risk. On this occasion that risk paid off, had it not then I could potentially have had one of my spare email addresses sold to Spammers, but am unlikely to have lost any money. Everything in life is a risk, and whilst it is better to err to the side of caution, paranoia is not always the healthiest feeling, especially if you are trying to make money. Simply put, trust no-one but give everyone a chance.