How to effectively recognize SCAMs & SPAMS

With lot of spams and scams lurking around and the con artists getting better and better all the time I thought I would compile up my set of warning signals. Feel free to comment anything I miss out.

• You are offered prize for a contest you never participated.
• You are picked in a lucky draw, and to claim the reward you have to pay some money. (You ll surely lose every penny you pay)
• You are asked to pay for a chance to participate in a bid that might get you something at an unbelievably low price. (Its like lottery right? I may win or not, but then again how do you know that dealcent.com actually picks a winner?)
• The website offers free membership, but to activate your account you need to fill out your credit card details. (Don't blame your insurance company that they 'll not settle your claims for some crap purchased of your card in Nigeria by a con man)
• You are asked to participate in a marketing scheme, your earnings depending on number of people you join for the scheme. Warning sign: there is no real product associated in the scheme/the product associated with scheme doesn't have the profit margin equivalent to the membership fees applicable
• You are asked to deposit money in an account via unsecure means (eg:direct bank transfer to account) before delivery of material
• You are asked to deposit money in an account via unsecure means (eg:direct bank transfer to account) for delivery of a material illegal in your country
• Overseas travel at your own expenses required to claim the prize
• The email claims to be from ebay/amazon/your bank but the return address is from a free account from yahoo/gmail than the from the original domain
• You do not know the sender or have any association with the organisation the sender claims to be
• The sender is listed in http://www.consumerfraudreporting.org/
• You are redirected to a login page that looks like your bank/email login page but the url is from some other domain
• The website of the offer has millions of testimonials and statistics, but it is never mentioned in your circle of friends nor on any other public forum online
• You are the 1000000th visitor of the site
• The product claims to provide benefits only after a prolonged duration (few months to years) and is not certified by any credible agency
• Shortened url depicting porn or sensationalized news posted in social networks
• Websites requiring to enter username and password of other unrelated companies eg: google/yahoo/fb  (these use open id so you shouldn't be entering your credentials anywhere else)
• You are one among 100s of email ids in the to field and there is no one group that relates you to them.

Let me know your warning list!!!