gistfile1.js

{
    "user": {
        "profile_text_color": "333333",
        "url": null,
        "listed_count": 4,
        "created_at": "Tue Jun 10 13:03:54 +0000 2008",
        "profile_sidebar_fill_color": "efefef",
        "screen_name": "virgiliocorrado",
        "contributors_enabled": false,
        "profile_background_tile": true,
        "time_zone": "Eastern Time (US & Canada)",
        "notifications": null,
        "favourites_count": 59,
        "lang": "en",
        "profile_link_color": "009999",
        "show_all_inline_media": false,
        "following": null,
        "geo_enabled": false,
        "profile_sidebar_border_color": "eeeeee",
        "description": "",
        "id_str": "15072741",
        "statuses_count": 25004,
        "friends_count": 507,
        "profile_use_background_image": true,
        "protected": false,
        "location": "the lightbulb moment centre",
        "follow_request_sent": null,
        "profile_background_color": "01090d",
        "name": "virgiliocorrado",
        "is_translator": false,
        "profile_background_image_url": "http:\/\/a2.twimg.com\/a\/1295051201\/images\/themes\/theme14\/bg.gif",
        "id": 15072741,
        "verified": false,
        "utc_offset": -18000,
        "followers_count": 231,
        "profile_image_url": "http:\/\/a0.twimg.com\/profile_images\/1128820290\/crabn_normal.jpg"
    },
    "in_reply_to_screen_name": "ginatrapani",
    "in_reply_to_status_id": null,
    "created_at": "Thu Jan 27 20:13:55 +0000 2011",
    "geo": null,
    "retweeted": false,
    "text": "@ginatrapani @jeffjarvis @leolaporte #TWIG topic? Google's Schmidt wants to set the record straight http:\/\/j.mp\/gc6y6Z http:\/\/is.gd\/6vHdJa",
    "source": "\u003Ca href=\"http:\/\/www.tweetdeck.com\" rel=\"nofollow\"\u003ETweetDeck\u003C\/a\u003E",
    "in_reply_to_status_id_str": null,
    "id_str": "30720175628099584",
    "entities": {
        "user_mentions": [{
            "indices": [0, 12],
            "screen_name": "ginatrapani",
            "id_str": "930061",
            "name": "Gina Trapani",
            "id": 930061
        },
        {
            "indices": [13, 24],
            "screen_name": "jeffjarvis",
            "id_str": "11435642",
            "name": "Jeff Jarvis",
            "id": 11435642
        },
        {
            "indices": [25, 36],
            "screen_name": "leolaporte",
            "id_str": "3829151",
            "name": "Leo Laporte",
            "id": 3829151
        }],
        "urls": [{
            "expanded_url": null,
            "url": "http:\/\/j.mp\/gc6y6Z",
            "indices": [100, 118]
        },
        {
            "expanded_url": null,
            "url": "http:\/\/is.gd\/6vHdJa",
            "indices": [119, 138]
        }],
        "hashtags": [{
            "indices": [37, 42],
            "text": "TWIG"
        }]
    },
    "contributors": null,
    "in_reply_to_user_id_str": "930061",
    "place": null,
    "coordinates": null,
    "retweet_count": 0,
    "truncated": false,
    "in_reply_to_user_id": 930061,
    "favorited": false,
    "id": 30720175628099584
}

gistfile2.go

type Hashtags struct {
    Indices                     []int
    Text                        string
}

type Urls struct {
    Url                         string
    Indices                     []int
    Display_url                 string
    Expanded_url                string
}

type User_mentions struct {
    Indices                     []int
    Screen_name                 string
    Id_str                      string
    Name                        string
    Id                          int64
}
 
type Entities struct {
    Hashtags                    *Hashtags
    Urls                        *Urls
    User_mentions               *User_mentions
}

type User struct {
    Lang                         string
    Verified                     bool
    Followers_count              int
    Location                     string
    Screen_name                  string
    Following                    bool
    Friends_count                int
    Profile_background_color     string
    Favourites_count             int
    Description                  string
    Notifications                string
    Profile_text_color           string
    Url                          string
    Time_zone                    string
    Statuses_count               int
    Profile_link_color           string
    Geo_enabled                  bool
    Profile_background_image_url string
    Protected                    bool
    Contributors_enabled         bool
    Profile_sidebar_fill_color   string
    Name                         string
    Profile_background_tile      string
    Created_at                   string
    Profile_image_url            string
    Id                           int64
    Id_str                       string
    Utc_offset                   int
    Profile_sidebar_border_color string
}

type Tweet struct {
    Text                        string
    Truncated                   bool
    Geo                         string
    In_reply_to_screen_name     string
    Favorited                   bool
    Source                      string
    Contributors                string
    In_reply_to_status_id       string
    In_reply_to_user_id         int64
    Id                          int64
    Created_at                  string
    Entities                    *Entities
    User                        *User
}

The Entities section is where I hit trouble. I suspect that I need a map for the the hashtags, url's and user mentions sections.

JSON objects only support strings as keys; to encode a Go map type it must be of the form map[string]T (where T is any Go type supported by the json package).

Via http://blog.golang.org/2011/01/json-and-go.html

Go structures taken from https://github.com/hoisie/twitterstream/blob/master/types.go