I think the warning is a problem, because I have the same issue and when I try to run my application I get this error:
=> Started proxy.
=> Started MongoDB.
client/app.ts (2, 27): Cannot find module '@angular/core'.
Compiling main app HTML file: client/index.html
Unable to resolve some modules:
"reflect-metadata" in client/app.js (web.browser)
"@angular/core" in node_modules/@angular/platform-browser-dynamic/index.js (web.browser)
"@angular/common" in node_modules/@angular/platform-browser-dynamic/index.js (web.browser)
"@angular/compiler" in node_modules/@angular/platform-browser-dynamic/src/xhr/xhr_cache.js (web.browser)
"@angular/platform-browser" in node_modules/@angular/platform-browser-dynamic/index.js (web.browser)
"rxjs/Subject" in node_modules/@angular/platform-browser-dynamic/src/facade/async.js (web.browser)
"rxjs/observable/PromiseObservable" in node_modules/@angular/platform-browser-dynamic/src/facade/async.js (web.browser)
"rxjs/operator/toPromise" in node_modules/@angular/platform-browser-dynamic/src/facade/async.js (web.browser)
"rxjs/Observable" in node_modules/@angular/platform-browser-dynamic/src/facade/async.js (web.browser)
If you notice problems related to these missing modules, consider running:
meteor npm install --save reflect-metadata @angular rxjs
This is because it requires specifically rc.1, but rc.3 is the latest since a few weeks.
Unfortunately it seems a lot of Angular2 packages are not getting attention…
As I can see you trying Socially tutorial. From my experience I recommend to use Meteor 1.3.2 instead of higher 1.3.4 or other, cause 1.3.4, for example, will require to you to change some code and fix some issues related to packages dependency.