Plenty of spam to go around
Spam accounts for the vast majority of e-mail traffic. Figures I've read range from 60% to 97% and something in between does not seem unreasonable. Unfortunately, there is no real penalty for spamming and many unwitting people's malware-infested PC's do it, so with the low risk of the real culprits getting caught, it is worth the tiny risk for them to try to scam you out of some cash. The typical spam message most people receive is stuff about drugs (especially Cialis, Viagra or Canadian pharmacies), Nigerian 419 scams, penile enlargement, fake degrees, stock hot market "tips" and stuff like that. When you have a website or at least own a domain name, you will likely receive some other insideous stuff too. Here's some examples.
Got this one recently. Bad grammar not fixed and names/telephone numbers
removed to protect the innocent :
Now Search Engine Optimisation is not necessarily a bad thing, as long as improving your site's attractiveness to search engines also results in a better user experience for the actual visitors to your site. Search engines love nicely structured sites with original, authoritative content and will reward you for it. This is known as white-hat SEO. On the other hand, there is also black-hat SEO, which uses dubious practices that are against search engines' guidelines and attempt to game the system. Matt Cutts and his webspam team at Google are focussed on weeding out this practice and penalising sites that do this. Any company that is willing to spam you to get your SEO business is also likely unscrupulous enough to use black-hat tactics. You might end up paying hundreds or thousands of dollars that you're effectively spending on destroying your search engine ranking and reputation!
Funnily enough, the spammers send these so carelessly that you could end up getting a "helpful offer" to improve the rankings for www.hotmail.com, just because you have an @hotmail.com e-mail address. Or what about this spammer offering to improve Google's own rankings?
Domain name registrations must be renewed at regular intervals. In most cases yearly. Failure to do so may cause the domain to be cybersquatted and can at least result in some funny or embarassing situations. Therefore this spammer gallantly offered to rescue me from that fate:
If my domain registrar sent me an e-mail to warn me of impending domain expiration, I'd be grateful. They do, and I am. Registering a .com domain typically costs between $10 and $15/yr, with services such as Hover (Tucows), 1&1 or Namecheap. That immediately explains why they're so eager to "help"... they'll charge you 5 times or more the going market rate for renewing your domain. If you fall for this scam, you will not only pay through the nose (and validate their unethical business model), but your domain will also be transferred to this crooked registrar and you most likely will not get the same level service that you had from your existing provider. Of course, if you do let the domain lapse, these cybercriminals will often attempt to quickly register your domain and hold it for ransom, charging you hundreds (and more likely: thousands) of dollars for the privilege of buying back what you already own(ed).
Of course I haven't really "elected to receive special notifications and offers", they're just putting in that disclaimer to keep up the appearance of a legitimate business. Also, reading the message properly does mention in a somewhat underhanded way that it's not actually a real order/invoice ("There is no obligation to pay for this order unless you complete your payment").
Whatever you do, never ever buy anything offered to you by way of an unsollicited commercial e-mail (or anything you did not explicitly sign up for). They send out millions of those at no cost to them and if even 1% of 1% of their victims gives them business, that still means they have hundreds of gullible morons as customers validating their business model and resulting in even more spam.