If a browser includes the Adobe Flash Player plugin (formerly developed by Macromedia), the Local Shared Objects functionality can be used in a way very similar to cookies. Local Shared Objects may be an attractive choice to web developers because a majority of Windows users have Flash Player installed, the default size limit is 100 kB, and the security controls are distinct from the user controls for cookies, so Local Stored Objects may be enabled when cookies are not.

In some cases, web sites have created Flash LSOs that behave differently than what a user specifies for their http cookies, which has raised concern that web sites need to specify a consistent privacy policy across different types of cookies. 

The major drawback with this approach is the same as every platform/vendor-specific approach: it breaks the web's global accessibility and interoperability, tying up web development to a specific client's platform, excluding users who use standards-compliant web user agents and instead forcing them to use platform/vendor-specific web agents, which perpetuates vendor lock-in.

Tracking
Drawbacks of cookies
Setting a cookie
Adobe Flash Local Shared Objects