meteor 初学者的几个问题请教

[richman2012]

1。npm install xxx和meteor npm install xxx
效果是一样的吗？有区别吗？
meteor add 是把npm install的包添加进去的意思吗？

2。meteor add ian:accounts-ui-bootstrap-3
之后显示
accounts-base added, version 1.0.1
anti:i18n added, version 0.4.3
ian:accounts-ui-bootstrap-3 added, version 1.2.89
localstorage added, version 1.0.12
service-configuration added, version 1.0.1
session added, version 1.0.5
stylus added, version 1.0.7

但是 meteor list 看不到上述包被add。
accounts-password 1.1.10* Password support for accounts
blaze-html-templates 1.0.5 Compile HTML templates into reactive UI w...
ecmascript 0.6.1 Compiler plugin that supports ES2015+ in ...
es5-shim 4.6.15 Shims and polyfills to improve ECMAScrip...
ian:accounts-ui-bootstrap-3 1.2.89 Bootstrap-styled accounts-ui with multi-...
insecure 1.0.7 (For prototyping only) Allow all database...
iron:router 1.0.13 Routing specifically designed for Meteor
jquery 1.11.10 Manipulate the DOM using CSS selectors
meteor-base 1.0.4 Packages that every Meteor app needs
mobile-experience 1.0.4 Packages for a great mobile user experience
mongo 1.1.14 Adaptor for using MongoDB and Minimongo ...
npm-bcrypt 0.9.2 Wrapper around the bcrypt npm package
reactive-var 1.0.11 Reactive variable
sacha:spin 2.3.1 Simple spinner package for Meteor
shell-server 0.2.1 Server-side component of the `meteor shel...
standard-minifier-css 1.3.2 Standard css minifier used with Meteor ap...
standard-minifier-js 1.2.1 Standard javascript minifiers used with M...
tracker 1.1.1 Dependency tracker to allow reactive call...
twbs:bootstrap 3.3.6 The most popular front-end framework for ...
underscore 1.0.10 Collection of small helpers: _.map, _.ea...

并且app启动时报错
meteor
=> Errors prevented startup:
While building for web.browser:
error: no plugin found for accounts_ui.styl in ian:accounts-ui-bootstrap-3;
a plugin for *.styl was active when it was published but none is now

我觉得应该是stylus的问题，但是meteor add stylus后依然不行。
meteor list
略
stylus 1.0.7* Expressive, dynamic, robust CSS
略

3.中文教程里提到
>又或者，你可以通过传递 Helper 的第二个参数，来明确指定需要找的 _id 在哪里。
>例如，{{pathFor 'postPage' someOtherPost}}。实际情况下，
>如果要获取帖子列表中前一个或者后一个的链接，我们就会使用这种模式。
以上第三个参数到底怎么用不太理解？能帮忙举个具体的例子吗？

[richman2012]