Tailing n. : The part of a projecting stone or brick inserted in a wall.

Tailing n. : Same as Tail, n., 8 (a).

Tailing n. : Sexual intercourse.

Tailing n. : The lighter parts of grain separated from the seed threshing and winnowing; chaff.

Tailing n. : The refuse part of stamped ore, thrown behind the tail of the buddle or washing apparatus. It is dressed over again to secure whatever metal may exist in it. Called also tails.

Example:
What do you do when someone is Tailing you?

Taxonomy
merchant, e-tailing, strategists, multi-channel, selling strategies, customer experiences, Industry Pioneers, promoters, best-in-class, customer service, Researchers, Developers, proprietary, mystery shopping, survey research, Category-specific, Industry benchmarks, In-depth.

Defination from the web:
Strategic planning and consulting for online merchants.