First of all being a Tout is already a bad sign, since it is a sign that you can not make a living out of betting but this is another sign:
The ranking of their website in Alexa. It could be to low(high number) or it coul be getting worse over time which is even worse.
For example, among the websites selling picks the best ranking is probably covers with 4,823, second is vegas insider 15,335, in the other hand toptencappers is 1,245,854, they has been getting worse over time which means they are losing their client at fast speed. I believe to remember they were in a rank under 300 000 but their traffic history has been removed from alexa. Toptencappers is owned by Wunderdog and their leaderboard record is a scam, that's probably why they are losing it.