Sharepoint History Column is a rich text column that tracks all editing posts history and authors in a conversation manner.
Each time user edits a comment on task - new history record with comment, author and date is added.
Common scenarios when Sharepoint History Column could be used are:

Comments on some topic or task;
Conversation field on some list item (topic, knowledge base, etc );
Sharepoint History Column brings user-friendly way to see history of previous text changes, authors and date for single list item rich text column at one place without tracking history for the whole list item.

History Column provides rich text / full html editor, past records editing, collapse/expand older records feature, newer/older records ordering.

History Column supports customizable rendering in list mode view and is compatible with MOSS 2007 and Sharepoint 2010 now.

When to use Sharepoint History Column ?
Sharepoint History Column brings easy-to-use comments history support for single text field in the list item.

• Sharepoint Fields Package 2.8
  Sharepoint Fields Package provides custom Sharepoint Fields. History Column is a rich text column that tracks all editing posts history and authors in a conversation...

• SharePoint Discussion Column 1.7.818.5
  SharePoint Discussion Column is a custom column to record users' discussion when they edit the item

• Discussion Column for SharePoint 1.51
  Discussion Column is intended to organize conversation in the list item without need to enable list versioning

• SharePoint Column Protector 1.2.6.14
  Hiding columns on SharePoint lists

• SharePoint Cross-Site Lookup Pack 2.14.105.0
  A cross-site lookup pack consists of SharePoint Cross-Site Lookup and SharePoint Cascaded Lookup extends SharePoint lookup function with new features

• SharePoint Permission Batch Setting 1.17.1209.
  Batching assign permissions to all items separated from list permission settings

• SharePoint Column/View Permission 2.2.811.0
  Assign read or edit permissions to columns

• SharePoint Permission Workflow 2.3.1215.3
  Auto set permission to item when it created or modified

• SPList Export for SharePoint 2007 5.0
  SPList Export for SharePoint 2010 (SPListX) is a powerful application to export document / picture library contents and associated metadata and list items, including associated file attachments to the Windows File System