Websites: VirusTotal

VirusTotal is a great online virus scanner, a Google subsidiary.
You can either scan a local file, or submit a remote URL; you can also search the database by file hash (SHA256, SHA1, MD5 etc.).
There's also a rating system for registered users.
Warning: all files you try to scan using this online service are actually get uploaded onto the remote server (or "cloud") for scanning, and subsequently can be shared with antivirus software developers in the future, so you should avoid scanning any confidential documents with this service ;-)
By uploading new malware, we can somehow improve the contemporary anti-virus solutions!

Links:

• home page,
  • currently, loading some kind of Web-2.0-styled uploader;
• rather old-style home page (unfortunately, apparently discontinued).

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Last updated: 2019-04-24

Websites: BugMeNot (shared logins)

Have you ever visited an ugly site requiring registration to access some ordinary info? Tired of countless one-time registrations?
BugMeNot can help: it's the site where you and other ordinary users can share their useless login info (disposable email addresses are usually used for such registrations) for a variety of useless sites :-)

Disclaimer: no warranties, only for educational use, some sites get blocked from the site, and please don't abuse it etc. ;-)

External links:

0. BugMeNot: share logins
   
   -1. microsoft.com passwords - BugMeNot
1. BugMeNot - Wikipedia