I do not know if this is possible, or if this is even prohibited, but here goes.

I am creating a website where I talk a lot about the web and different programming languages. Now I want to create rollovers for certain words, and display a little summary of what it is, just like when you rollover the tag in SE. Now I have looked in the API documentation, but I could not find this feature.

{
  "total": {
    "description": "total number of items in this sequence",
    "values": "32-bit integer, range [0, 2,147,483,647]",
    "optional": false
  },
  "page": {
    "description": "page of the total collection returned",
    "values": "32-bit integer, range [1, 2,147,483,647]",
    "optional": false
  },
  "pagesize": {
    "description": "size of each page returned from the collection",
    "values": "32-bit integer, range [0, 100]",
    "optional": false
  },
  "tags": [
    {
      "name": {
        "description": "name of the tag",
        "values": "string",
        "optional": false,
        "suggested_buffer_size": 25
      },
      "count": {
        "description": "tag count, exact meaning depends on context",
        "values": "32-bit signed integer",
        "optional": false
      },
      "restricted_to": {
        "description": "user types that can make use of this tag, lack of this field indicates it is useable by all",
        "values": "one of anonymous, unregistered, registered, or moderator",
        "optional": true
      },
      "fulfills_required": {
        "description": "indicates whether this tag is one of those that is required to be on a post",
        "values": "boolean",
        "optional": false
      },
      "user_id": {
        "description": "user associated with this tag, depends on context",
        "values": "32-bit signed integer",
        "optional": true
      }
    }
  ]
}

No mention of the info, for example:

http://stackoverflow.com/tags/html/info