Spam refers to unsolicited bulk messages sent to multiple recipients. There are different types of spam, such as junk email messages containing advertisements, viruses, or chain letters. Receiving spam is problematic because it can overload email inboxes and spread viruses. If you receive spam, you should delete it and not respond or forward chain letters and other spam messages. You should also scan email attachments from unknown senders for viruses before opening them. Ways to reduce spam include using spam filters, not opening suspicious messages or attachments, and being careful about sharing personal information online.