求微博内部人员曝个内幕,5位uid是如何发放的?

最近在采集微博用户数据,期间发现了一些6位的微博帐号,之后又发现了5位的,注册时间11年,已经很晚了,怎么会被分配到这么靠前的id, 求答疑解惑.数据如下:

{
"id": 98765,
"idstr": "98765",
"screen_name": "chafang",
"name": "chafang",
"province": "44",
"city": "5",
"location": "广东 汕头",
"description": "",
"url": "",
"profile_image_url": "http://tp2.sinaimg.cn/98765/50/0/1",
"profile_url": "uc98765",
"domain": "uc98765",
"weihao": "",
"gender": "m",
"followers_count": 0,
"friends_count": 0,
"statuses_count": 0,
"favourites_count": 0,
"created_at": "Mon Dec 19 23:17:56 +0800 2011",
"following": false,
"allow_all_act_msg": false,
"geo_enabled": true,
"verified": false,
"verified_type": -1,
"remark": "",
"allow_all_comment": true,
"avatar_large": "http://tp2.sinaimg.cn/98765/180/0/1",
"verified_reason": "",
"follow_me": false,
"online_status": 0,
"bi_followers_count": 0,
"lang": "zh-cn",
"star": 0,
"mbtype": 0,
"mbrank": 0,
"block_word": 0
}