Dating websites need to be approached and handled with great caution, no matter what your age is. It is dangerous to assume that you are safe just because of your age or any other factor. You need to be very careful as to what information you give out about yourself, and always let a trusted friend or relative know if you plan to meet up with someone you have connected with in “cyberspace”, so that they can have your back if you encounter something unexpected. Don’t let your desire for companionship override your common sense and discretion.
They are safe only if you take the neccessary precautions. For example, as the others have mentioned, do not give out important information about yourself, and do not give out money to anyone over the internet no matter how desperate they sound, or even if you love them. There are many scammers out there who play on the emotions of vulnerable lovelorn people for their own benefit. Have discretion!
Senior dating sites are a good way to get to know like-minded people with the same demographics, but as with all forms of online dating, care and precaution has to be taken to ensure one's safety. Be sure not to give out personal information such as addresses, bank or credit card details to anyone online to make sure that you are not scammed.
I would be careful about making friends on dating sites. From the experience a friend of mine had from an online dating site, which ended in a disastrous marriage, I would not recommend it. People present the best of themselves and omit to tell you the bad parts. It would be better to join organisations where you can get together with like-minded people and meet them face-to-face. It is still no guarantee that you will find the perfect person but it will give you a better idea of who they really are if you can observe their interactions with others.